Atomic surface structure for unraveling the trade-off between the propane dehydrogenation activity and anti-deactivation of PtSn catalysts

In commercial Pt-based propane dehydrogenation catalysts, Sn doping is a fascinating strategy to suppress side reactions and optimize selectivity. Nevertheless, excessive Sn incorporation results in a decline in surface Pt sites, leading to a significant reduction in catalytic activity. It challenges the precision of surface chemical design and the atomic unraveling of surface coordination is critical to resolving the inherent trade-off between catalytic activity and anti-deactivation. In this work, we modulated PtSn catalyst surface structures by controlling the Sn content, achieving optimal activity, anti-deactivation, and selectivity. Building upon the average structural characterization, we further resolved three-dimensional atomic configurations and extracted surface structures of catalysts by integrating the Reverse Monte Carlo method with pair distribution function analysis. It was found that the increasing Sn content enhances anti-deactivation by reducing surface Pt-Pt coordination numbers; this effect reaches saturation when the coordination number on the surface approaches approximately 3. Beyond this critical threshold, additional Sn incorporation compromises activity through Pt site blockage while offering a negligible effect on anti-deactivation. These findings provide clear guidelines for the rational surface design of nanocatalysts and synthesis of high-performance platinum-based catalysts with superior catalytic properties.